| Objective To investigate the effects on neurones apoptosis of hippocampus and expression of apoptosis related genes after transient cerebral ischemia and reperfusion in old rats.Methods the acute global cerebral ischemia model was produced with 100 old healthy Wistar rats by four-vossel occlusion as described by Pusinelli.The rats were randomed divided into four groups,that was ischemia 1min group, ischemia 3min group, ischemia 5min group,sham-operation group,25 rats in every group.Then every group was divided into five sub-groups by reperfusion time,that was reperfusion 12h group, reperfusion 1d group, reperfusion 2d group, reperfusion 3d group, reperfusion 7d group,5 rats in every sub-group, we utilized histopathology technique and transmission electron microscope to observe neuron ultrastructure, meanwhile the neurones apoptosis in hippocampus was detected by TUNEL method,and the expression of Caspase-3 protein was detected by SABC immunohistochemical technique.Results There were a few TUNEL-positive cells and expression of Caspase-3 protein in sham-operation group and ischemia lmin group, meanwhile TUNEL-positive cells and expression of Caspase-3 protein in ischemia 3min group and ischemia 5min group were raised significiently. In ischemia 3min group and ischemia 5min group positive cells appeared after ischemia 12 hours, got to the fastigium after ischemia ldays,and went down 3 days later. Electron microscope in CA1 region indicated typical apoptotic occurrence, such as chromatin edging, nuclei pycnosis, et al.Conclusion The aged brain was more sensitive to cerebral ischemia/reperfusion injury,and the TUNEL-positive cells and expression of Caspase-3 protein in hippocampus were raised significiently only after transient cerebral ischemia. There was a significient relativity between neuroal cell apoptosis and Caspase-3 protein. The neuron apoptosis and the expression of Caspase-3 protein increased with reperfusion time longer, and showedearlier and lasted longer in the aged. |
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